Photoresist composition and method of forming photoresist pattern

ABSTRACT

A photoresist composition includes a conjugated resist additive, a photoactive compound, and a polymer resin. The conjugated resist additive is one or more selected from the group consisting of a polyacetylene, a polythiophene, a polyphenylenevinylene, a polyfluorene, a polypryrrole, a polyphenylene, and a polyaniline. The polyacetylene, polythiophene, polyphenylenevinylene, polyfluorene, polypryrrole, the polyphenylene, and polyaniline includes a substituent selected from the group consisting of an alkyl group, an ether group, an ester group, an alkene group, an aromatic group, an anthracene group, an alcohol group, an amine group, a carboxylic acid group, and an amide group. Another photoresist composition includes a polymer resin having a conjugated moiety and a photoactive compound. The conjugated moiety is one or more selected from the group consisting of a polyacetylene, a polythiophene, a polyphenylenevinylene, a polyfluorene, a polypryrrole, a polyphenylene, and a polyaniline.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional application of U.S. application Ser.No. 16/584,234, filed Sep. 26, 2019, which claims priority to U.S.Provisional Patent Application No. 62/742,773, filed Oct. 8, 2018, theentire disclosure of each of which are incorporated herein by reference.

BACKGROUND

As consumer devices have gotten smaller and smaller in response toconsumer demand, the individual components of these devices havenecessarily decreased in size as well. Semiconductor devices, which makeup a major component of devices such as mobile phones, computer tablets,and the like, have been pressured to become smaller and smaller, with acorresponding pressure on the individual devices (e.g., transistors,resistors, capacitors, etc.) within the semiconductor devices to also bereduced in size.

One enabling technology that is used in the manufacturing processes ofsemiconductor devices is the use of photolithographic materials. Suchmaterials are applied to a surface of a layer to be patterned and thenexposed to an energy that has itself been patterned. Such an exposuremodifies the chemical and physical properties of the exposed regions ofthe photosensitive material. This modification, along with the lack ofmodification in regions of the photosensitive material that were notexposed, can be exploited to remove one region without removing theother.

However, as the size of individual devices has decreased, processwindows for photolithographic processing has become tighter and tighter.As such, advances in the field of photolithographic processing arenecessary to maintain the ability to scale down the devices, and furtherimprovements are needed in order to meet the desired design criteriasuch that the march towards smaller and smaller components may bemaintained.

As the semiconductor industry has progressed into nanometer technologyprocess nodes in pursuit of higher device density, higher performance,and lower costs, there have been challenges in reducing semiconductorfeature size. Extreme ultraviolet lithography (EUVL) has been developedto form smaller semiconductor device feature size and increase devicedensity on a semiconductor wafer. In order to improve EUVL an increasein wafer exposure throughput is desirable. Wafer exposure throughput canbe improved through increased exposure power or increased resistphotospeed. Low exposure dose may lead to reduced line width resolutionand reduced critical dimension uniformity.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is best understood from the following detaileddescription when read with the accompanying figures. It is emphasizedthat, in accordance with the standard practice in the industry, variousfeatures are not drawn to scale and are used for illustration purposesonly. In fact, the dimensions of the various features may be arbitrarilyincreased or reduced for clarity of discussion.

FIG. 1 illustrates a process flow of manufacturing a semiconductordevice according to embodiments of the disclosure.

FIG. 2 shows a process stage of a sequential operation according to anembodiment of the disclosure.

FIGS. 3A and 3B show a process stage of a sequential operation accordingto an embodiment of the disclosure.

FIG. 4 shows a process stage of a sequential operation according to anembodiment of the disclosure.

FIG. 5 shows a process stage of a sequential operation according to anembodiment of the disclosure.

FIG. 6 shows a process stage of a sequential operation according to anembodiment of the disclosure.

FIGS. 7A and 7B show photoresist composition components according tosome embodiments of the disclosure.

FIG. 8 shows a process stage of a sequential operation according to anembodiment of the disclosure.

FIGS. 9A and 9B show a process stage of a sequential operation accordingto an embodiment of the disclosure.

FIG. 10 shows a process stage of a sequential operation according to anembodiment of the disclosure.

FIG. 11 shows a process stage of a sequential operation according to anembodiment of the disclosure.

FIG. 12 shows a process stage of a sequential operation according to anembodiment of the disclosure.

DETAILED DESCRIPTION

It is to be understood that the following disclosure provides manydifferent embodiments, or examples, for implementing different featuresof the disclosure. Specific embodiments or examples of components andarrangements are described below to simplify the present disclosure.These are, of course, merely examples and are not intended to belimiting. For example, dimensions of elements are not limited to thedisclosed range or values, but may depend upon process conditions and/ordesired properties of the device. Moreover, the formation of a firstfeature over or on a second feature in the description that follows mayinclude embodiments in which the first and second features are formed indirect contact, and may also include embodiments in which additionalfeatures may be formed interposing the first and second features, suchthat the first and second features may not be in direct contact. Variousfeatures may be arbitrarily drawn in different scales for simplicity andclarity.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The device may be otherwise oriented (rotated 90 degrees orat other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly. In addition, the term“made of” may mean either “comprising” or “consisting of.”

FIG. 1 illustrates a process flow 100 of manufacturing a semiconductordevice according to embodiments of the disclosure. A photoresist iscoated on a surface of a layer to be patterned or a substrate 10 inoperation S110, in some embodiments, to form a photoresist layer 15, asshown in FIG. 2 . Then the photoresist layer 15 undergoes a first bakingoperation S120 to evaporate solvents in the photoresist composition insome embodiments. The photoresist layer 15 is baked at a temperature andtime sufficient to cure and dry the photoresist layer 15. In someembodiments, the photoresist layer is heated to a temperature of about40° C. and 120° C. for about 10 seconds to about 10 minutes.

After the first baking operation S120, the photoresist layer 15 isselectively exposed to actinic radiation 45/97 (see FIGS. 3A and 3B) inoperation S130. In some embodiments, the photoresist layer 15 isselectively exposed to ultraviolet radiation. In some embodiments, theultraviolet radiation is deep ultraviolet radiation (DUV). In someembodiments, the ultraviolet radiation is extreme ultraviolet (EUV)radiation. In some embodiments, the radiation is an electron beam.

As shown in FIG. 3A, the exposure radiation 45 passes through aphotomask 30 before irradiating the photoresist layer 15 in someembodiments. In some embodiments, the photomask has a pattern to bereplicated in the photoresist layer 15. The pattern is formed by anopaque pattern 35 on the photomask substrate 40, in some embodiments.The opaque pattern 35 may be formed by a material opaque to ultravioletradiation, such as chromium, while the photomask substrate 40 is formedof a material that is transparent to ultraviolet radiation, such asfused quartz.

In some embodiments, the selective exposure of the photoresist layer 15to form exposed regions 50 and unexposed regions 52 is performed usingextreme ultraviolet lithography. In an extreme ultraviolet lithographyoperation a reflective photomask 65 is used to form the patternedexposure light, as shown in FIG. 3B. The reflective photomask 65includes a low thermal expansion glass substrate 70, on which areflective multilayer 75 of Si and Mo is formed. A capping layer 80 andabsorber layer 85 are formed on the reflective multilayer 75. A rearconductive layer 90 is formed on the back side of the low thermalexpansion substrate 70. In extreme ultraviolet lithography, extremeultraviolet radiation 95 is directed towards the reflective photomask 65at an incident angle of about 6°. A portion 97 of the extremeultraviolet radiation is reflected by the Si/Mo multilayer 75 towardsthe photoresist-coated substrate 10, while the portion of the extremeultraviolet radiation incident upon the absorber layer 85 is absorbed bythe photomask. In some embodiments, additional optics, includingmirrors, are between the reflective photomask 65 and thephotoresist-coated substrate.

The region of the photoresist layer exposed to radiation 50 undergoes achemical reaction thereby changing its solubility in a subsequentlyapplied developer relative to the region of the photoresist layer notexposed to radiation 52. In some embodiments, the portion of thephotoresist layer exposed to radiation 50 undergoes a crosslinkingreaction.

Next, the photoresist layer 15 undergoes a post-exposure bake inoperation S140. In some embodiments, the photoresist layer 15 is heatedto a temperature of about 50° C. and 160° C. for about 20 seconds toabout 120 seconds. The post-exposure baking may be used in order toassist in the generating, dispersing, and reacting of the acid/base/freeradical generated from the impingement of the radiation 45/97 upon thephotoresist layer 15 during the exposure. Such assistance helps tocreate or enhance chemical reactions which generate chemical differencesbetween the exposed region 50 and the unexposed region 52 within thephotoresist layer. These chemical differences also cause differences inthe solubility between the exposed region 50 and the unexposed region52.

The selectively exposed photoresist layer is subsequently developed byapplying a developer to the selectively exposed photoresist layer inoperation S150. As shown in FIG. 4 , a developer 57 is supplied from adispenser 62 to the photoresist layer 15. In some embodiments, theexposed portion of the photoresist layer 50 is removed by the developer57 forming a pattern of openings 55 in the photoresist layer 15 toexpose the substrate 20, as shown in FIG. 5 .

In some embodiments, the pattern of openings 55 in the photoresist layer15 are extended into the layer to be patterned or substrate 10 to createa pattern of openings 55′ in the substrate 10, thereby transferring thepattern in the photoresist layer 15 into the substrate 10, as shown inFIG. 6 . The pattern is extended into the substrate by etching, usingone or more suitable etchants. The unexposed photoresist layer 15 is atleast partially removed during the etching operation in someembodiments. In other embodiments, the unexposed photoresist layer 15 isremoved after etching the substrate 10 by using a suitable photoresiststripper solvent or by a photoresist ashing operation.

In some embodiments, the substrate 10 includes a single crystallinesemiconductor layer on at least it surface portion. The substrate 10 mayinclude a single crystalline semiconductor material such as, but notlimited to Si, Ge, SiGe, GaAs, InSb, GaP, GaSb, InAlAs, InGaAs, GaSbP,GaAsSb and InP. In some embodiments, the substrate 10 is a silicon layerof an SOI (silicon-on insulator) substrate. In certain embodiments, thesubstrate 10 is made of crystalline Si.

The substrate 10 may include in its surface region, one or more bufferlayers (not shown). The buffer layers can serve to gradually change thelattice constant from that of the substrate to that of subsequentlyformed source/drain regions. The buffer layers may be formed fromepitaxially grown single crystalline semiconductor materials such as,but not limited to Si, Ge, GeSn, SiGe, GaAs, InSb, GaP, GaSb, InAlAs,InGaAs, GaSbP, GaAsSb, GaN, GaP, and InP. In an embodiment, the silicongermanium (SiGe) buffer layer is epitaxially grown on the siliconsubstrate 10. The germanium concentration of the SiGe buffer layers mayincrease from 30 atomic % for the bottom-most buffer layer to 70 atomic% for the top-most buffer layer.

In some embodiments, the substrate 10 includes one or more layers of atleast one metal, metal alloy, and metal/nitride/sulfide/oxide/silicidehaving the formula MX_(a), where M is a metal and X is N, S, Se, O, Si,and a is from about 0.4 to about 2.5. In some embodiments, the substrate10 includes titanium, aluminum, cobalt, ruthenium, titanium nitride,tungsten nitride, tantalum nitride, and combinations thereof.

In some embodiments, the substrate 10 includes a dielectric having atleast a silicon or metal oxide or nitride of the formula MX_(b), where Mis a metal or Si, X is N or O, and b ranges from about 0.4 to about 2.5.In some embodiments, the substrate 10 includes silicon dioxide, siliconnitride, aluminum oxide, hafnium oxide, lanthanum oxide, andcombinations thereof.

The photoresist layer 15 is a photosensitive layer that is patterned byexposure to actinic radiation. Typically, the chemical properties of thephotoresist regions struck by incident radiation change in a manner thatdepends on the type of photoresist used. Photoresist layers 15 areeither positive tone resists or negative tone resists. A positive toneresist refers to a photoresist material that when exposed to radiation,such as UV light, becomes soluble in a developer, while the region ofthe photoresist that is non-exposed (or exposed less) is insoluble inthe developer. A negative tone resist, on the other hand, refers to aphotoresist material that when exposed to radiation becomes insoluble inthe developer, while the region of the photoresist that is non-exposed(or exposed less) is soluble in the developer. The region of a negativeresist that becomes insoluble upon exposure to radiation may becomeinsoluble due to a cross-linking reaction caused by the exposure toradiation.

Whether a resist is a positive tone or negative tone may depend on thetype of developer used to develop the resist. For example, some positivetone photoresists provide a positive pattern, (i.e.—the exposed regionsare removed by the developer), when the developer is an aqueous-baseddeveloper, such as a tetramethylammonium hydroxide (TMAH) solution. Onthe other hand, the same photoresist provides a negative pattern(i.e.—the unexposed regions are removed by the developer) when thedeveloper is an organic solvent. Further, in some negative tonephotoresists developed with the TMAH solution, the unexposed regions ofthe photoresist are removed by the TMAH, and the exposed regions of thephotoresist, that undergo cross-linking upon exposure to actinicradiation, remain on the substrate after development.

In some embodiments, the photoresist layer includes a high sensitivityphotoresist composition. In some embodiments, the high sensitivityphotoresist composition is highly sensitive to extreme ultraviolet (EUV)radiation. According to embodiments of the disclosure, a highsensitivity photoresist includes a conjugated material in thephotoresist composition. The conjugated material is an oligomer orpolymer as a resist unit, additive, or resist unit and additive mixturein some embodiments. In some embodiments, the conjugated material is aconjugated moiety in the main chain of a polymer, or a pendant moiety orsidechain of a polymer. In some embodiments, the material is aconjugated functionalized photoacid generator (PAG), photo-decomposablebase (PDB), or a photobase generator (PBG).

In some embodiments, the weight average molecular weight of theconjugated material ranges from about 50 to about 1,000,000. In someembodiments, the weight average molecular weight of the conjugatedmaterial ranges from about 2500 to about 750,000. In some embodiments,the weight average molecular weight of the conjugated material rangesfrom about 5,000 to about 500,000. In some embodiments, an R groupsubstituent on the conjugated material improves the photoresist contrastby improving solubility of the photoresist composition components,including photo-switch components. The R substituent on the conjugatedmaterial is polar group, non-polar group, an acid leaving group (ALG),or an additional conjugated group or mixture of different R substituentsin some embodiments. In some embodiments, the R substituent helps toadjust the electronic properties through electron-donating orwithdrawing behaviors.

The conjugated material provides a longer path for photons to beabsorbed in the photoresist, and a longer lifetime of delocalizedelectrons, and thus, more efficient acid or base generation by photoacidor photobase generators. The conjugated material provides greaterelectron and hole generation, and higher energy transfer efficiency at10 nm to 200 nm wavelengths.

Conjugated materials according to embodiments of the disclosure areshown in FIGS. 7A and 7B. Conjugated materials according to someembodiments have a low band gap. The band gap of some conjugatedmaterials according to embodiments of the disclosure are shown in FIG.7A. In some embodiments, the band gap ranges from about 0.3 eV to about4 eV. In other embodiments, the band gap ranges from about 1 eV to about3 eV. In some embodiments, the conjugated materials make theelectron/hole delocalization, and then increases the electron/holelifetime for the energy transfer (i.e.—e→PAG). Furthermore, theconjugated system is also able to illuminate light (150˜1000 nm) thatmay be absorbed by the photoacid generator (PAG) thereby increasing theacid yield.

The conjugated material is a conjugated resist additive in someembodiments and is moiety attached to a polymer resin in otherembodiments. As shown in FIG. 7A, conjugated resist additives orconjugated resist polymer moieties according to embodiments of thedisclosure include a polyacetylene, a polythiophene, apolyphenylenevinylene, a polyfluorene, a polypryrrole, a polyphenylene,and a polyaniline. The number of repeating units of the monomers nranges from 1 to about 500. In some embodiments, the conjugated resistadditives or polymer moieties include one or more substituents R. Asshown in FIG. 7A, the substituents R may be an alkyl group, an ethergroup, an ester group, an alkene group, an aromatic group, an anthracenegroup, an alcohol group, an amine group, a carboxylic acid group, or anamide group, where n ranges from 1 to about 200. The substituents mayimprove solubility during development of the photoresist. In anembodiment, the one or more substituents include an acid leaving group.In an embodiment, an acid leaving group is attached to alcohol groupsubstituent or a carboxylic acid group substituent. In an embodiment,the conjugated resist additive includes a conjugated moiety attached toa photoacid generator, a photo-decomposable base, or a photobasegenerator. In an embodiment, the conjugated resist additive has a weightaverage molecular weight of 50 to 1,000,000.

In some embodiments, the conjugated resist additive includes:

where PAG is a photoacid generator, PBG is a photobase generator, andPDB is a photo-decomposable base, and R is a substituent selected fromthe group consisting of an alkyl group, an ether group, an ester group,an alkene group, an aromatic group, an anthracene group, an alcoholgroup, an amine group, a carboxylic acid group, or an amide group. Insome embodiments, the substituent groups are repeating units where thenumber of repeating units n ranges from 1 to about 200.

In some embodiments, the polymer resin with a conjugated moiety includes

where R is an alkyl group, an ether group, an ester group, an alkenegroup, an aromatic group, an anthracene group, an alcohol group, anamine group, a carboxylic acid group, or an amide group. In someembodiments, the substituents are repeating groups where the number ofrepeating groups n ranges from 1 to about 200.

In some embodiments, the conjugated moieties are either repeating unitsin the main chain of the polymer, repeating units of a pendant groupattached to the main chain of the polymer resin, or repeating units ofan end group attached to an end of the main chain of the polymer resin.

In some embodiments, the photoresist composition includes a polymerresin having a first conjugated moiety, and a photoactive compoundhaving a second conjugated moiety. The first and second conjugatedmoieties are the same or different and the first and second conjugatedmoieties are one or more selected from the polyacetylene, polythiophene,polyphenylenevinylene, polyfluorene, polypryrrole, polyphenylene, andpolyaniline described herein in reference to FIG. 7A.

In some embodiments, photoresist compositions according to the presentdisclosure include a metal oxide nanoparticle and one or more organicligands. In some embodiments, the metal oxide nanoparticle is anorganometallic including one or more metal oxides nanoparticles selectedfrom the group consisting of titanium dioxide, zinc oxide, zirconiumdioxide, nickel oxide, cobalt oxide, manganese oxide, copper oxides,iron oxides, strontium titanate, tungsten oxides, vanadium oxides,chromium oxides, tin oxides, hafnium oxide, indium oxide, cadmium oxide,molybdenum oxide, tantalum oxides, niobium oxide, aluminum oxide, andcombinations thereof. As used herein, nanoparticles are particles havingan average particle size between about 1 nm and about 20 nm. In someembodiments, the metal oxide nanoparticles have an average particle sizebetween about 2 nm and about 5 nm. In some embodiments, the amount ofmetal oxide nanoparticles in the photoresist composition ranges fromabout 1 wt. % to about 15 wt. % based on the weight of the firstsolvent. In some embodiments, the amount of nanoparticles in thephotoresist composition ranges from about 5 wt. % to about 10 wt. %based on the weight of the first solvent. Below about 1 wt. % metaloxide nanoparticles the photoresist coating is too thin. Above about 15wt. % metal oxide nanoparticles the photoresist coating is too thick.

In some embodiments, the metal oxide nanoparticles are complexed with aligand. In some embodiments, the ligand is a carboxylic acid or sulfonicacid ligand. For example, in some embodiments, zirconium oxide orhafnium oxide nanoparticles are complexed with methacrylic acid forminghafnium methacrylic acid (HfMAA) or zirconium (ZrMAA) methacrylic acid.In some embodiments, the metal oxide nanoparticles are complexed withligands including aliphatic or aromatic groups. The aliphatic oraromatic groups may be unbranched or branched with cyclic or noncyclicsaturated pendant groups containing 1-9 carbons, including alkyl groups,alkenyl groups, and phenyl groups. The branched groups may be furthersubstituted with oxygen or halogen.

In some embodiments, the photoresist composition includes about 0.1 wt.% to about 20 wt. % of the ligand. In some embodiments, the photoresistincludes about 1 wt. % to about 10 wt. % of the ligand. In someembodiments, the ligand concentration is about 10 wt. % to about 40 wt.% based on the weight of the metal oxide nanoparticles. Below about 10wt. % ligand the organometallic photoresist does not function well.Above about 40 wt. % ligand it is hard to form the photoresist layer. Insome embodiments, the ligand is HfMAA or ZrMAA dissolved at about a 5wt. % to about 10 wt. % weight range in a coating solvent, such aspropylene glycol methyl ether acetate (PGMEA).

In some embodiments, the polymer resins and the PACs, along with anydesired additives or other agents, are added to the solvent forapplication. Once added, the mixture is then mixed in order to achieve ahomogenous composition throughout the photoresist to ensure that thereare no defects caused by uneven mixing or nonhomogeneous composition ofthe photoresist. Once mixed together, the photoresist may either bestored prior to its usage or used immediately.

The solvent can be any suitable solvent. In some embodiments, thesolvent is one or more selected from propylene glycol methyl etheracetate (PGMEA), propylene glycol monomethyl ether (PGME),1-ethoxy-2-propanol (PGEE), γ-butyrolactone (GBL), cyclohexanone (CHN),ethyl lactate (EL), methanol, ethanol, propanol, n-butanol, acetone,dimethylformamide (DMF), isopropanol (IPA), tetrahydrofuran (THF),methyl isobutyl carbinol (MIBC), n-butyl acetate (nBA), and 2-heptanone(MAK).

In some embodiments, the photoresist composition further includes waterat a concentration of 10 ppm to 250 ppm based on the total compositionof the water, enhancement additive, and first solvent.

In some embodiments, the photoresist composition includes a polymerresin along with one or more photoactive compounds (PACs). In someembodiments, the polymer resin includes a hydrocarbon structure (such asan alicyclic hydrocarbon structure) that contains one or more groupsthat will decompose (e.g., acid labile groups) or otherwise react whenmixed with acids, bases, or free radicals generated by the PACs (asfurther described below). In some embodiments, the hydrocarbon structureincludes a repeating unit that forms a skeletal backbone of the polymerresin. This repeating unit may include acrylic esters, methacrylicesters, crotonic esters, vinyl esters, maleic diesters, fumaricdiesters, itaconic diesters, (meth)acrylonitrile, (meth)acrylamides,styrenes, vinyl ethers, combinations of these, or the like.

Specific structures that are utilized for the repeating unit of thehydrocarbon structure in some embodiments, include one or more of methylacrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butylacrylate, isobutyl acrylate, tert-butyl acrylate, n-hexyl acrylate,2-ethylhexyl acrylate, acetoxyethyl acrylate, phenyl acrylate,2-hydroxyethyl acrylate, 2-methoxyethyl acrylate, 2-ethoxyethylacrylate, 2-(2-methoxyethoxy)ethyl acrylate, cyclohexyl acrylate, benzylacrylate, 2-alkyl-2-adamantyl (meth)acrylate ordialkyl(1-adamantyl)methyl (meth)acrylate, methyl methacrylate, ethylmethacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butylmethacrylate, isobutyl methacrylate, tert-butyl methacrylate, n-hexylmethacrylate, 2-ethylhexyl methacrylate, acetoxyethyl methacrylate,phenyl methacrylate, 2-hydroxyethyl methacrylate, 2-methoxyethylmethacrylate, 2-ethoxyethyl methacrylate, 2-(2-methoxyethoxy)ethylmethacrylate, cyclohexyl methacrylate, benzyl methacrylate,3-chloro-2-hydroxypropyl methacrylate, 3-acetoxy-2-hydroxypropylmethacrylate, 3-chloroacetoxy-2-hydroxypropyl methacrylate, butylcrotonate, hexyl crotonate, or the like. Examples of the vinyl estersinclude vinyl acetate, vinyl propionate, vinyl butylate, vinylmethoxyacetate, vinyl benzoate, dimethyl maleate, diethyl maleate,dibutyl maleate, dimethyl fumarate, diethyl fumarate, dibutyl fumarate,dimethyl itaconate, diethyl itaconate, dibutyl itaconate, acrylamide,methyl acrylamide, ethyl acrylamide, propyl acrylamide, n-butylacrylamide, tert-butyl acrylamide, cyclohexyl acrylamide, 2-methoxyethylacrylamide, dimethyl acrylamide, diethyl acrylamide, phenyl acrylamide,benzyl acrylamide, methacrylamide, methyl methacrylamide, ethylmethacrylamide, propyl methacrylamide, n-butyl methacrylamide,tert-butyl methacrylamide, cyclohexyl methacrylamide, 2-methoxyethylmethacrylamide, dimethyl methacrylamide, diethyl methacrylamide, phenylmethacrylamide, benzyl methacrylamide, methyl vinyl ether, butyl vinylether, hexyl vinyl ether, methoxyethyl vinyl ether, dimethylaminoethylvinyl ether, or the like. Examples of styrenes include styrene, methylstyrene, dimethyl styrene, trimethyl styrene, ethyl styrene, isopropylstyrene, butyl styrene, methoxy styrene, butoxy styrene, acetoxystyrene, hydroxy styrene, chloro styrene, dichloro styrene, bromostyrene, vinyl methyl benzoate, α-methyl styrene, maleimide,vinylpyridine, vinylpyrrolidone, vinylcarbazole, combinations of these,or the like.

In some embodiments, the polymer resin is a polyhydroxystyrene, apolymethyl methacrylate, or a polyhydroxystyrene-t-butyl acrylate, e.g.—

In some embodiments, the repeating unit of the hydrocarbon structurealso has either a monocyclic or a polycyclic hydrocarbon structuresubstituted into it, or the monocyclic or polycyclic hydrocarbonstructure is the repeating unit, in order to form an alicyclichydrocarbon structure. Specific examples of monocyclic structures insome embodiments include bicycloalkane, tricycloalkane,tetracycloalkane, cyclopentane, cyclohexane, or the like. Specificexamples of polycyclic structures in some embodiments includeadamantane, norbornane, isobornane, tricyclodecane, tetracyclododecane,or the like.

In some embodiments, the polymer resin includes any of the conjugatedmoieties described herein in reference to FIGS. 7A and 7B. Theconjugated moieties are either repeating units in the main chain of thepolymer, repeating units of a pendant group attached to the main chainof the polymer resin, or repeating units of an end group of the mainchain of the polymer resin.

The group which will decompose, otherwise known as a leaving group or,in some embodiments in which the PAC is a photoacid generator, an acidlabile group, is attached to the hydrocarbon structure so that, it willreact with the acids/bases/free radicals generated by the PACs duringexposure. In some embodiments, the group which will decompose is acarboxylic acid group, a fluorinated alcohol group, a phenolic alcoholgroup, a sulfonic group, a sulfonamide group, a sulfonylimido group, an(alkylsulfonyl) (alkylcarbonyl)methylene group, an(alkylsulfonyl)(alkyl-carbonyl)imido group, abis(alkylcarbonyl)methylene group, a bis(alkylcarbonyl)imido group, abis(alkylsylfonyl)methylene group, a bis(alkylsulfonyl)imido group, atris(alkylcarbonyl methylene group, a tris(alkylsulfonyl)methylenegroup, combinations of these, or the like. Specific groups that are usedfor the fluorinated alcohol group include fluorinated hydroxyalkylgroups, such as a hexafluoroisopropanol group in some embodiments.Specific groups that are used for the carboxylic acid group includeacrylic acid groups, methacrylic acid groups, or the like.

In some embodiments, the polymer resin also includes other groupsattached to the hydrocarbon structure that help to improve a variety ofproperties of the polymerizable resin. For example, inclusion of alactone group to the hydrocarbon structure assists to reduce the amountof line edge roughness after the photoresist has been developed, therebyhelping to reduce the number of defects that occur during development.In some embodiments, the lactone groups include rings having five toseven members, although any suitable lactone structure may alternativelybe used for the lactone group.

In some embodiments, the polymer resin includes groups that can assistin increasing the adhesiveness of the photoresist layer 15 to underlyingstructures (e.g., substrate 10). Polar groups may be used to helpincrease the adhesiveness. Suitable polar groups include hydroxylgroups, cyano groups, or the like, although any suitable polar groupmay, alternatively, be used.

Optionally, the polymer resin includes one or more alicyclic hydrocarbonstructures that do not also contain a group, which will decompose insome embodiments. In some embodiments, the hydrocarbon structure thatdoes not contain a group which will decompose includes structures suchas 1-adamantyl(meth)acrylate, tricyclodecanyl (meth)acrylate, cyclohexyl(methacrylate), combinations of these, or the like.

Some embodiments of the photoresist include one or more photoactivecompounds (PACs). The PACs are photoactive components, such as photoacidgenerators (PAG), photobase (PBG) generators, photo decomposable bases(PDB), free-radical generators, or the like. The PACs may bepositive-acting or negative-acting. In some embodiments in which thePACs are a photoacid generator, the PACs include halogenated triazines,onium salts, diazonium salts, aromatic diazonium salts, phosphoniumsalts, sulfonium salts, iodonium salts, imide sulfonate, oximesulfonate, diazodisulfone, disulfone, o-nitrobenzylsulfonate, sulfonatedesters, halogenated sulfonyloxy dicarboximides, diazodisulfones,α-cyanooxyamine-sulfonates, imidesulfonates, ketodiazosulfones,sulfonyldiazoesters, 1,2-di(arylsulfonyl)hydrazines, nitrobenzyl esters,and the s-triazine derivatives, combinations of these, or the like.

Specific examples of photoacid generators includeα-(trifluoromethylsulfonyloxy)-bicyclo[2.2.1]hept-5-ene-2,3-dicarb-o-ximide(MDT), N-hydroxy-naphthalimide (DDSN), benzoin tosylate,t-butylphenyl-α-(p-toluenesulfonyloxy)-acetate andt-butyl-α-(p-toluenesulfonyloxy)-acetate, triarylsulfonium anddiaryliodonium hexafluoroantimonates, hexafluoroarsenates,trifluoromethanesulfonates, iodonium perfluorooctanesulfonate,N-camphorsulfonyloxynaphthalimide,N-pentafluorophenylsulfonyloxynaphthalimide, ionic iodonium sulfonatessuch as diaryl iodonium (alkyl or aryl)sulfonate andbis-(di-t-butylphenyl)iodonium camphanylsulfonate,perfluoroalkanesulfonates such as perfluoropentanesulfonate,perfluorooctanesulfonate, perfluoromethanesulfonate, aryl (e.g., phenylor benzyl)triflates such as triphenylsulfonium triflate orbis-(t-butylphenyl)iodonium triflate; pyrogallol derivatives (e.g.,trimesylate of pyrogallol), trifluoromethanesulfonate esters ofhydroxyimides, α,α′-bis-sulfonyl-diazomethanes, sulfonate esters ofnitro-substituted benzyl alcohols, naphthoquinone-4-diazides, alkyldisulfones, or the like.

In some embodiments, the PAG is attached to one of the conjugatedmaterials disclosed herein in reference to FIGS. 7A and 7B.

In some embodiments in which the PACs are free-radical generators, thePACs include n-phenylglycine; aromatic ketones, including benzophenone,N,N′-tetramethyl-4,4′-diaminobenzophenone,N,N′-tetraethyl-4,4′-diaminobenzophenone,4-methoxy-4′-dimethylaminobenzo-phenone,3,3′-dimethyl-4-methoxybenzophenone,p,p′-bis(dimethylamino)benzo-phenone,p,p′-bis(diethylamino)-benzophenone; anthraquinone,2-ethylanthraquinone; naphthaquinone; and phenanthraquinone; benzoinsincluding benzoin, benzoinmethylether, benzoinisopropylether,benzoin-n-butylether, benzoin-phenylether, methylbenzoin andethylbenzoin; benzyl derivatives, including dibenzyl,benzyldiphenyldisulfide, and benzyldimethylketal; acridine derivatives,including 9-phenylacridine, and 1,7-bis(9-acridinyl)heptane;thioxanthones, including 2-chlorothioxanthone, 2-methylthioxanthone,2,4-diethylthioxanthone, 2,4-dimethylthioxanthone, and2-isopropylthioxanthone; acetophenones, including1,1-dichloroacetophenone, p-t-butyldichloro-acetophenone,2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, and2,2-dichloro-4-phenoxyacetophenone; 2,4,5-triarylimidazole dimers,including 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer,2-(o-chlorophenyl)-4,5-di-(m-methoxyphenyl imidazole dimer,2-(o-fluorophenyl)-4,5-diphenylimidazole dimer,2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer,2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer,2,4-di(p-methoxyphenyl)-5-phenylimidazole dimer,2-(2,4-dimethoxyphenyl)-4,5-diphenylimidazole dimer and2-(p-methylmercaptophenyl)-4,5-diphenylimidazole dimmer; combinations ofthese, or the like.

In some embodiments, the PAC includes a quencher. In some embodiments,the quenchers include photobase generators and photo decomposable bases.In embodiments in which the PACs are photobase generators (PBG), thePBGs include quaternary ammonium dithiocarbamates, a aminoketones,oxime-urethane containing molecules such as dibenzophenoneoximehexamethylene diurethan, ammonium tetraorganylborate salts, andN-(2-nitrobenzyloxycarbonyl)cyclic amines, combinations of these, or thelike.

In some embodiments in which the PACs are photo decomposable bases(PDB), the PDBs include triphenylsulfonium hydroxide, triphenylsulfoniumantimony hexafluoride, and triphenylsulfonium trifyl.

In some embodiments, the PBG and PDB are attached to one of theconjugated materials disclosed herein in reference to FIGS. 7A and 7B.

As one of ordinary skill in the art will recognize, the chemicalcompounds listed herein are merely intended as illustrated examples ofthe PACs and are not intended to limit the embodiments to only thosePACs specifically described. Rather, any suitable PAC may be used, andall such PACs are fully intended to be included within the scope of thepresent embodiments.

In some embodiments, a cross-linking agent is added to the photoresist.The cross-linking agent reacts with one group from one of thehydrocarbon structures in the polymer resin and also reacts with asecond group from a separate one of the hydrocarbon structures in orderto cross-link and bond the two hydrocarbon structures together. Thisbonding and cross-linking increases the molecular weight of the polymerproducts of the cross-linking reaction and increases the overall linkingdensity of the photoresist. Such an increase in density and linkingdensity helps to improve the resist pattern.

In some embodiments the cross-linking agent has the following structure:

wherein C is carbon, n ranges from 1 to 15; A and B independentlyinclude a hydrogen atom, a hydroxyl group, a halide, an aromatic carbonring, or a straight or cyclic alkyl, alkoxyl/fluoro, alkyl/fluoroalkoxylchain having a carbon number of between 1 and 12, and each carbon Ccontains A and B; a first terminal carbon C at a first end of a carbon Cchain includes X and a second terminal carbon C at a second end of thecarbon chain includes Y, wherein X and Y independently include an aminegroup, a thiol group, a hydroxyl group, an isopropyl alcohol group, oran isopropyl amine group, except when n=1 then X and Y are bonded to thesame carbon C. Specific examples of materials that may be used as thecross-linking agent include the following:

Alternatively, instead of or in addition to the cross-linking agentbeing added to the photoresist composition, a coupling reagent is addedin some embodiments, in which the coupling reagent is added in additionto the cross-linking agent. The coupling reagent assists thecross-linking reaction by reacting with the groups on the hydrocarbonstructure in the polymer resin before the cross-linking reagent,allowing for a reduction in the reaction energy of the cross-linkingreaction and an increase in the rate of reaction. The bonded couplingreagent then reacts with the cross-linking agent, thereby coupling thecross-linking agent to the polymer resin.

Alternatively, in some embodiments in which the coupling reagent isadded to the photoresist 12 without the cross-linking agent, thecoupling reagent is used to couple one group from one of the hydrocarbonstructures in the polymer resin to a second group from a separate one ofthe hydrocarbon structures in order to cross-link and bond the twopolymers together. However, in such an embodiment the coupling reagent,unlike the cross-linking agent, does not remain as part of the polymer,and only assists in bonding one hydrocarbon structure directly toanother hydrocarbon structure.

In some embodiments, the coupling reagent has the following structure:

where R is a carbon atom, a nitrogen atom, a sulfur atom, or an oxygenatom; M includes a chlorine atom, a bromine atom, an iodine atom, —NO₂;—SO₃—; —H—; —CN; —NCO, —OCN; —CO₂—; —OH; —OR*, —OC(O)CR*; —SR,—SO₂N(R*)₂; —SO₂R*; SOR; —OC(O)R*; —C(O)OR*; —C(O)R*; —Si(OR*)₃;—Si(R*)₃; epoxy groups, or the like; and R* is a substituted orunsubstituted C1-C12 alkyl, C1-C12 aryl, C1-C12 aralkyl, or the like.Specific examples of materials used as the coupling reagent in someembodiments include the following:

The individual components of the photoresist are placed into a solventin order to aid in the mixing and dispensing of the photoresist. To aidin the mixing and dispensing of the photoresist, the solvent is chosenat least in part based upon the materials chosen for the polymer resinas well as the PACs. In some embodiments, the solvent is chosen suchthat the polymer resin and the PACs can be evenly dissolved into thesolvent and dispensed upon the layer to be patterned.

Another quencher is added to some embodiments of the photoresistcomposition to inhibit diffusion of the generated acids/bases/freeradicals within the photoresist. The quencher improves the resistpattern configuration as well as the stability of the photoresist overtime. In an embodiment, the quencher is an amine, such as a second loweraliphatic amine, a tertiary lower aliphatic amine, or the like. Specificexamples of amines include trimethylamine, diethylamine, triethylamine,di-n-propylamine, tri-n-propylamine, tripentylamine, diethanolamine, andtriethanolamine, alkanolamine, combinations thereof, or the like.

In some embodiments, an organic acid is used as the quencher. Specificembodiments of organic acids include malonic acid, citric acid, malicacid, succinic acid, benzoic acid, salicylic acid; phosphorous oxo acidand its derivatives, such as phosphoric acid and derivatives thereofsuch as its esters, phosphoric acid di-n-butyl ester and phosphoric aciddiphenyl ester; phosphonic acid and derivatives thereof such as itsester, such as phosphonic acid dimethyl ester, phosphonic aciddi-n-butyl ester, phenylphosphonic acid, phosphonic acid diphenyl ester,and phosphonic acid dibenzyl ester; and phosphinic acid and derivativesthereof such as its esters, including phenylphosphinic acid.

Another additive added to some embodiments of the photoresist is astabilizer, which assists in preventing undesired diffusion of the acidsgenerated during exposure of the photoresist. In some embodiments, thestabilizer includes nitrogenous compounds, including aliphatic primary,secondary, and tertiary amines; cyclic amines, including piperidines,pyrrolidines, morpholines; aromatic heterocycles, including pyridines,pyrimidines, purines; imines, including diazabicycloundecene,guanidines, imides, amides, or the like. Alternatively, ammonium saltsare also be used for the stabilizer in some embodiments, includingammonium, primary, secondary, tertiary, and quaternary alkyl- andaryl-ammonium salts of alkoxides, including hydroxide, phenolates,carboxylates, aryl and alkyl sulfonates, sulfonamides, or the like.Other cationic nitrogenous compounds, including pyridinium salts andsalts of other heterocyclic nitrogenous compounds with anions, such asalkoxides, including hydroxide, phenolates, carboxylates, aryl and alkylsulfonates, sulfonamides, or the like, are used in some embodiments.

Another additive in some embodiments of the photoresist is a dissolutioninhibitor to help control dissolution of the photoresist duringdevelopment. In an embodiment bile-salt esters may be utilized as thedissolution inhibitor. Specific examples of dissolution inhibitors insome embodiments include cholic acid, deoxycholic acid, lithocholicacid, t-butyl deoxycholate, t-butyl lithocholate, and t-butyl-3-acetyllithocholate.

Another additive in some embodiments of the photoresist is aplasticizer. Plasticizers may be used to reduce delamination andcracking between the photoresist and underlying layers (e.g., the layerto be patterned). Plasticizers include monomeric, oligomeric, andpolymeric plasticizers, such as oligo- and polyethyleneglycol ethers,cycloaliphatic esters, and non-acid reactive steroidaly-derivedmaterials. Specific examples of materials used for the plasticizer insome embodiments include dioctyl phthalate, didodecyl phthalate,triethylene glycol dicaprylate, dimethyl glycol phthalate, tricresylphosphate, dioctyl adipate, dibutyl sebacate, triacetyl glycerine, orthe like.

A coloring agent is another additive included in some embodiments of thephotoresist. The coloring agent observers examine the photoresist andfind any defects that may need to be remedied prior to furtherprocessing. In some embodiments, the coloring agent is a triarylmethanedye or a fine particle organic pigment. Specific examples of materialsin some embodiments include crystal violet, methyl violet, ethyl violet,oil blue #603, Victoria Pure Blue BOH, malachite green, diamond green,phthalocyanine pigments, azo pigments, carbon black, titanium oxide,brilliant green dye (C. I. 42020), Victoria Pure Blue FGA (Linebrow),Victoria BO (Linebrow) (C. I. 42595), Victoria Blue BO (C. I. 44045),rhodamine 6G (C. I. 45160), benzophenone compounds, such as2,4-dihydroxybenzophenone and 2,2′,4,4′-tetrahydroxybenzophenone;salicylic acid compounds, such as phenyl salicylate and 4-t-butylphenylsalicylate; phenylacrylate compounds, such asethyl-2-cyano-3,3-diphenylacrylate, andT-ethylhexyl-2-cyano-3,3-diphenylacrylate; benzotriazole compounds, suchas 2-(2-hydroxy-5-methylphenyl)-2H-benzotriazole, and2-(3-t-butyl-2-hydroxy-5-methylphenyl)-5-chloro-2H-benzotriazole;coumarin compounds, such as 4-methyl-7-diethylamino-1-benzopyran-2-one;thioxanthone compounds, such as diethylthioxanthone; stilbene compounds,naphthalic acid compounds, azo dyes, phthalocyanine blue, phthalocyaninegreen, iodine green, Victoria blue, crystal violet, titanium oxide,naphthalene black, Photopia methyl violet, bromphenol blue andbromcresol green; laser dyes, such as Rhodamine G6, Coumarin 500, DCM(4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H pyran)),Kiton Red 620, Pyrromethene 580, or the like. Additionally, one or morecoloring agents may be used in combination to provide the desiredcoloring.

Adhesion additives are added to some embodiments of the photoresist topromote adhesion between the photoresist and an underlying layer uponwhich the photoresist has been applied (e.g., the layer to bepatterned). In some embodiments, the adhesion additives include a silanecompound with at least one reactive substituent such as a carboxylgroup, a methacryloyl group, an isocyanate group and/or an epoxy group.Specific examples of the adhesion components include trimethoxysilylbenzoic acid, γ-methacryloxypropyl trimethoxy silane,vinyltriacetoxysilane, vinyltrimethoxysilane, γ-isocyanatepropyltriethoxy silane, γ-glycidoxypropyl trimethoxy silane,β-(3,4-epoxycyclohexyl)ethyl trimethoxy silane, benzimidazoles andpolybenzimidazoles, a lower hydroxyalkyl substituted pyridinederivative, a nitrogen heterocyclic compound, urea, thiourea, anorganophosphorus compound, 8-oxyquinoline, 4-hydroxypteridine andderivatives, 1,10-phenanthroline and derivatives, 2,2′-bipyridine andderivatives, benzotriazoles, organophosphorus compounds,phenylenediamine compounds, 2-amino-1-phenylethanol,N-phenylethanolamine, N-ethyldiethanolamine, N-ethylethanolamine andderivatives, benzothiazole, and a benzothiazoleamine salt having acyclohexyl ring and a morpholine ring,3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane,3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxy silane,3-methacryloyloxypropyltrimethoxysilane, vinyl trimethoxysilane,combinations thereof, or the like.

Surface leveling agents are added to some embodiments of the photoresistto assist a top surface of the photoresist to be level, so thatimpinging light will not be adversely modified by an unlevel surface. Insome embodiments, surface leveling agents include fluoroaliphaticesters, hydroxyl terminated fluorinated polyethers, fluorinated ethyleneglycol polymers, silicones, acrylic polymer leveling agents,combinations thereof, or the like.

In some embodiments, the polymer resin and the PACs, along with anydesired additives or other agents, are added to the solvent forapplication. Once added, the mixture is then mixed in order to achieve ahomogenous composition throughout the photoresist to ensure that thereare no defects caused by uneven mixing or nonhomogenous composition ofthe photoresist. Once mixed together, the photoresist may either bestored prior to its usage or used immediately.

Once ready, the photoresist is applied onto the layer to be patterned,as shown in FIG. 2 , such as the substrate 10 to form a photoresistlayer 15. In some embodiments, the photoresist is applied using aprocess such as a spin-on coating process, a dip coating method, anair-knife coating method, a curtain coating method, a wire-bar coatingmethod, a gravure coating method, a lamination method, an extrusioncoating method, combinations of these, or the like. In some embodiments,the photoresist layer 15 thickness ranges from about 10 nm to about 300nm.

After the photoresist layer 15 has been applied to the substrate 10, apre-bake of the photoresist layer is performed in some embodiments tocure and dry the photoresist prior to radiation exposure (see FIG. 1 ).The curing and drying of the photoresist layer 15 removes the solventcomponent while leaving behind the polymer resin, the PACs, thecross-linking agent, and the other chosen additives. In someembodiments, the pre-baking is performed at a temperature suitable toevaporate the solvent, such as between about 50° C. and 120° C.,although the precise temperature depends upon the materials chosen forthe photoresist. The pre-baking is performed for a time sufficient tocure and dry the photoresist layer, such as between about 10 seconds toabout 10 minutes.

FIGS. 3A and 3B illustrate selective exposures of the photoresist layerto form an exposed region 50 and an unexposed region 52. In someembodiments, the exposure to radiation is carried out by placing thephotoresist-coated substrate in a photolithography tool. Thephotolithography tool includes a photomask 30/65, optics, an exposureradiation source to provide the radiation 45/97 for exposure, and amovable stage for supporting and moving the substrate under the exposureradiation.

In some embodiments, the radiation source (not shown) supplies radiation45/97, such as ultraviolet light, to the photoresist layer 15 in orderto induce a reaction of the PACs, which in turn reacts with the polymerresin to chemically alter those regions of the photoresist layer towhich the radiation 45/97 impinges. In some embodiments, the radiationis electromagnetic radiation, such as g-line (wavelength of about 436nm), i-line (wavelength of about 365 nm), ultraviolet radiation, farultraviolet radiation, extreme ultraviolet, electron beams, or the like.In some embodiments, the radiation source is selected from the groupconsisting of a mercury vapor lamp, xenon lamp, carbon arc lamp, a KrFexcimer laser light (wavelength of 248 nm), an ArF excimer laser light(wavelength of 193 nm), an F₂ excimer laser light (wavelength of 157nm), or a CO₂ laser-excited Sn plasma (extreme ultraviolet, wavelengthof 13.5 nm).

In some embodiments, optics (not shown) are used in the photolithographytool to expand, reflect, or otherwise control the radiation before orafter the radiation 45/97 is patterned by the photomask 30/65. In someembodiments, the optics include one or more lenses, mirrors, filters,and combinations thereof to control the radiation 45/97 along its path.

In an embodiment, the patterned radiation 45/97 is extreme ultravioletlight having a 13.5 nm wavelength, the PAC is a photoacid generator, thegroup to be decomposed is a carboxylic acid group on the hydrocarbonstructure, and a cross linking agent is used. The patterned radiation45/97 impinges upon the photoacid generator, and the photoacid generatorabsorbs the impinging patterned radiation 45/97. This absorptioninitiates the photoacid generator to generate a proton (e.g., a H⁺ atom)within the photoresist layer 15. When the proton impacts the carboxylicacid group on the hydrocarbon structure, the proton reacts with thecarboxylic acid group, chemically altering the carboxylic acid group andaltering the properties of the polymer resin in general. The carboxylicacid group then reacts with the cross-linking agent in some embodimentsto cross-link with other polymer resins within the exposed region of thephotoresist layer 15.

In some embodiments, the exposure of the photoresist layer 15 uses animmersion lithography technique. In such a technique, an immersionmedium (not shown) is placed between the final optics and thephotoresist layer, and the exposure radiation 45 passes through theimmersion medium.

After the photoresist layer 15 has been exposed to the exposureradiation 45, a post-exposure baking is performed in some embodiments toassist in the generating, dispersing, and reacting of the acid/base/freeradical generated from the impingement of the radiation 45 upon the PACsduring the exposure. Such thermal assistance helps to create or enhancechemical reactions which generate chemical differences between theexposed region 50 and the unexposed region 52 within the photoresistlayer 15. These chemical differences also cause differences in thesolubility between the exposed region 50 and the unexposed region 52. Insome embodiments, the post-exposure baking occurs at temperaturesranging from about 50° C. to about 160° C. for a period of between about20 seconds and about 120 seconds.

The inclusion of the cross-linking agent into the chemical reactionshelps the components of the polymer resin (e.g., the individualpolymers) react and bond with each other, increasing the molecularweight of the bonded polymer in some embodiments. In particular, aninitial polymer has a side chain with a carboxylic acid protected by oneof the groups to be removed/acid labile groups. The groups to be removedare removed in a de-protecting reaction, which is initiated by a protonH⁺ generated by, e.g., the photoacid generator during either theexposure process or during the post-exposure baking process. The H⁺first removes the groups to be removed/acid labile groups and anotherhydrogen atom may replace the removed structure to form a de-protectedpolymer. Once de-protected, a cross-linking reaction occurs between twoseparate de-protected polymers that have undergone the de-protectingreaction and the cross-linking agent in a cross-linking reaction. Inparticular, hydrogen atoms within the carboxylic groups formed by thede-protecting reaction are removed and the oxygen atoms react with andbond with the cross-linking agent. This bonding of the cross-linkingagent to two polymers bonds the two polymers not only to thecross-linking agent but also bonds the two polymers to each otherthrough the cross-linking agent, thereby forming a cross-linked polymer.

By increasing the molecular weight of the polymers through thecross-linking reaction, the new cross-linked polymer becomes lesssoluble in conventional organic solvent negative resist developers.

In some embodiments, the photoresist developer 57 includes a solvent,and an acid or a base. In some embodiments, the concentration of thesolvent is from about 60 wt. % to about 99 wt. % based on the totalweight of the photoresist developer. The acid or base concentration isfrom about 0.001 wt. % to about 20 wt. % based on the total weight ofthe photoresist developer. In certain embodiments, the acid or baseconcentration in the developer is from about 0.01 wt. % to about 15 wt.% based on the total weight of the photoresist developer.

In some embodiments, the developer 57 is applied to the photoresistlayer 15 using a spin-on process. In the spin-on process, the developer57 is applied to the photoresist layer 15 from above the photoresistlayer 15 while the photoresist-coated substrate is rotated, as shown inFIG. 4 . In some embodiments, the developer 57 is supplied at a rate ofbetween about 5 ml/min and about 800 ml/min, while the photoresistcoated substrate 10 is rotated at a speed of between about 100 rpm andabout 2000 rpm. In some embodiments, the developer is at a temperatureof between about 10° C. and about 80° C. The development operationcontinues for between about 30 seconds to about 10 minutes in someembodiments.

While the spin-on operation is one suitable method for developing thephotoresist layer 15 after exposure, it is intended to be illustrativeand is not intended to limit the embodiment. Rather, any suitabledevelopment operations, including dip processes, puddle processes, andspray-on methods, may alternatively be used. All such developmentoperations are included within the scope of the embodiments.

During the development process, the developer 57 dissolves theradiation-exposed regions 50 of the cross-linked negative resist,exposing the surface of the substrate 10, as shown in FIG. 5 , andleaving behind well-defined unexposed photoresist regions 52, havingimproved definition than provided by conventional negative photoresistphotolithography.

After the developing operation S150, remaining developer is removed fromthe patterned photoresist covered substrate. The remaining developer isremoved using a spin-dry process in some embodiments, although anysuitable removal technique may be used. After the photoresist layer 15is developed, and the remaining developer is removed, additionalprocessing is performed while the patterned photoresist layer 52 is inplace. For example, an etching operation, using dry or wet etching, isperformed in some embodiments, to transfer the pattern of thephotoresist layer 52 to the underlying substrate 10, forming recesses55″ as shown in FIG. 6 . The substrate 10 has a different etchresistance than the photoresist layer 15. In some embodiments, theetchant is more selective to the substrate 10 than the photoresist layer15.

In some embodiments, the substrate 10 and the photoresist layer 15contain at least one etching resistance molecule. In some embodiments,the etching resistant molecule includes a molecule having a low Onishinumber structure, a double bond, a triple bond, silicon, siliconnitride, titanium, titanium nitride, aluminum, aluminum oxide, siliconoxynitride, combinations thereof, or the like.

In some embodiments, a layer to be patterned 60 is disposed over thesubstrate prior to forming the photoresist layer, as shown in FIG. 8 .In some embodiments, the layer to be patterned 60 is a metallizationlayer or a dielectric layer, such as a passivation layer, disposed overa metallization layer. In embodiments where the layer to be patterned 60is a metallization layer, the layer to be patterned 60 is formed of aconductive material using metallization processes, and metal depositiontechniques, including chemical vapor deposition, atomic layerdeposition, and physical vapor deposition (sputtering). Likewise, if thelayer to be patterned 60 is a dielectric layer, the layer to bepatterned 60 is formed by dielectric layer formation techniques,including thermal oxidation, chemical vapor deposition, atomic layerdeposition, and physical vapor deposition.

The photoresist layer 50 is subsequently selectively exposed to actinicradiation 45 to form exposed regions 50 and unexposed regions 52 in thephotoresist layer, as shown in FIGS. 9A and 9B, and described herein inrelation to FIGS. 3A and 3B. As explained herein the photoresist is anegative photoresist, wherein polymer crosslinking occurs in the exposedregions 50 in some embodiments.

As shown in FIG. 10 , the exposed photoresist regions 50 are developedby dispensing developer 57 from a dispenser 62 to form a pattern ofphotoresist openings 55, as shown in FIG. 11 . The development operationis similar to that explained with reference to FIGS. 4 and 5 , herein.

Then as shown in FIG. 12 , the pattern 55 in the photoresist layer 15 istransferred to the layer to be patterned 60 using an etching operationand the photoresist layer is removed, as explained with reference toFIG. 7 to form pattern 55″ in the layer to be patterned 60.

The novel photoresist compositions and photolithographic patterningmethods according to the present disclosure provide higher semiconductordevice feature resolution and density at higher wafer exposurethroughput with reduced defects in a higher efficiency process thanconventional exposure techniques. The novel photoresist compositionsprovide improved solubility of the photoresist components in thephotoresist composition.

An embodiment of the disclosure is a photoresist composition, includinga conjugated resist additive, a photoactive compound, and a polymerresin. The conjugated resist additive is one or more selected from thegroup consisting of a polyacetylene, a polythiophene, apolyphenylenevinylene, a polyfluorene, a polypryrrole, a polyphenylene,and a polyaniline. The polythiophene, polyphenylenevinylene,polyfluorene, polypryrrole, polyphenylene, and polyaniline aresubstituted with one or more substituents selected from the groupconsisting of an alkyl group, an ether group, an ester group, an alkenegroup, an aromatic group, an anthracene group, an alcohol group, anamine group, a carboxylic acid group, and an amide group. In anembodiment, the one or more substituents include an acid leaving group.In an embodiment, the conjugated resist additive has a band gap of 0.3eV to 4 eV. In an embodiment, the conjugated resist additive includes aconjugated moiety attached to a photoacid generator, a photodecomposable base, or a photobase generator. In an embodiment, theconjugated resist additive has a weight average molecular weight of 50to 1,000,000. In an embodiment, the composition includes metal oxidenanoparticles and one or more organic ligands. In an embodiment, thecomposition includes one or more solvents. In an embodiment, the polymerresin comprises

and the conjugated resist additive is selected from the group consistingof

where PAG is a photoacid generator, PBG is a photobase generator, andPDB is a photo-decomposable base, and R is the substituent.

Another embodiment of the disclosure is a photoresist composition,including a polymer resin having a conjugated moiety, and a photoactivecompound. The conjugated moiety is one or more selected from the groupconsisting of a polyacetylene, a polythiophene, a polyphenylenevinylene,a polyfluorene, a polypryrrole, a polyphenylene, and a polyaniline. Inan embodiment, the polythiophene, polyphenylenevinylene, polyfluorene,polyfluorene, polypryrrole, polyphenylene, and polyaniline aresubstituted with one or more substituents selected from the groupconsisting of an alkyl group, an ether group, an ester group, an alkenegroup, an aromatic group, an anthracene group, an alcohol group, anamine group, a carboxylic acid group, and an amide group. In anembodiment, the one or more substituents include an acid leaving group.In an embodiment, the polymer resin having a conjugated moiety has aweight average molecular weight of 50 to 1,000,000. In an embodiment,the photoresist composition includes metal oxide nanoparticles and oneor more organic ligands. In an embodiment, the polymer resin having aconjugated moiety is

and R is the substituent. In an embodiment, the photoresist compositionincludes one or more solvents. In an embodiment, the conjugated moietyis a repeating unit of a pendant group on a main chain of the polymerresin.

Another embodiment of the disclosure is a method of forming a pattern ina photoresist, including forming a photoresist composition layer over asubstrate, and selectively exposing the photoresist layer to actinicradiation to form a latent pattern. The latent pattern is developed byapplying a developer to the selectively exposed photoresist layer toform a pattern. The photoresist composition includes a conjugated resistadditive, a photoactive compound, and a polymer resin. The conjugatedresist additive is one or more selected from the group consisting of apolyacetylene, a polythiophene, a polyphenylenevinylene, a polyfluorene,a polypryrrole, a polyphenylene, and a polyaniline. In an embodiment,the polythiophene, polyphenylenevinylene, polyfluorene, polypryrrole,polyphenylene, and polyaniline are substituted with one or moresubstituents selected from the group consisting of an alkyl group, anether group, an ester group, an alkene group, an aromatic group, ananthracene group, an alcohol group, an amine group, a carboxylic acidgroup, and an amide group. In an embodiment, the actinic radiation isextreme ultraviolet radiation. In an embodiment, the method includesafter selectively exposing the photoresist layer to actinic radiation toform a latent pattern and before developing the latent pattern heatingthe photoresist layer. In an embodiment, the one or more substituentsinclude an acid leaving group. In an embodiment, the conjugated resistadditive has a band gap of 0.3 eV to 4 eV. In an embodiment, theconjugated resist additive includes a conjugated moiety attached to aphotoacid generator, a photo-decomposable base, or a photobasegenerator. In an embodiment, the conjugated resist additive has a weightaverage molecular weight of 50 to 1,000,000. In an embodiment, thephotoresist composition further comprising metal oxide nanoparticles andone or more organic ligands. In an embodiment, the photoresistcomposition includes one or more solvents. In an embodiment, the polymerresin includes

and the conjugated resist additive is selected from the group consistingof

where PAG is a photoacid generator, PBG is a photobase generator, andPDB is a photo-decomposable base, and R is the substituent.

Another embodiment of the disclosure is a method of forming a pattern ina photoresist, including forming a photoresist composition layer over asubstrate, and selectively exposing the photoresist layer to actinicradiation to form a latent pattern. The latent pattern is developed byapplying a developer to the selectively exposed photoresist layer toform a pattern. The photoresist composition includes a polymer resinhaving a conjugated moiety, and a photoactive compound. The conjugatedmoiety is one or more selected from the group consisting of apolyacetylene, a polythiophene, a polyphenylenevinylene, a polyfluorene,a polypryrrole, a polyphenylene, and a polyaniline. In an embodiment,the actinic radiation is extreme ultraviolet radiation. In anembodiment, the method includes after selectively exposing thephotoresist layer to actinic radiation to form a latent pattern andbefore developing the latent pattern heating the photoresist layer. Inan embodiment, the polythiophene, polyphenylenevinylene, polyfluorene,polypryrrole, polyphenylene, and polyaniline are substituted with one ormore substituents selected from the group consisting of an alkyl group,an ether group, an ester group, an alkene group, an aromatic group, ananthracene group, an alcohol group, an amine group, a carboxylic acidgroup, and an amide group. In an embodiment, the one or moresubstituents include an acid leaving group. In an embodiment, thepolymer resin having a conjugated moiety has a weight average molecularweight of 1,000 to 1,000,000. In an embodiment, the photoresistcomposition includes metal oxide nanoparticles and one or more organicligands. In an embodiment, the polymer resin having a conjugated moietyis

where R is the substituent. In an embodiment, the photoresistcomposition includes one or more solvents. In an embodiment, theconjugated moiety is a repeating unit of a pendant group on a main chainof the polymer resin.

Another embodiment of the disclosure is a photoresist composition,including a polymer resin having a first conjugated moiety, and aphotoactive compound having a second conjugated moiety. The first andsecond conjugated moieties are the same or different and the first andsecond conjugated moieties are one or more selected from the groupconsisting of a polyacetylene, a polythiophene, a polyphenylenevinylene,a polyfluorene, a polypryrrole, a polyphenylene, and a polyaniline. Inan embodiment, the polythiophene, polyphenylenevinylene, polyfluorene,polypryrrole, polyphenylene, and polyaniline are substituted with one ormore substituents selected from the group consisting of an alkyl group,an ether group, an ester group, an alkene group, an aromatic group, ananthracene group, an alcohol group, an amine group, a carboxylic acidgroup, and an amide group. In an embodiment, the one or moresubstituents include an acid leaving group, and the photoactive compoundis a photoacid generator. In an embodiment, the composition includesmetal oxide nanoparticles and one or more organic ligands.

Another embodiment of the disclosure is a method of forming a pattern ina photoresist, including forming a photoresist composition layer on asubstrate, and selectively exposing the photoresist layer to actinicradiation to form a latent pattern. The latent pattern is developed byapplying a developer to the selectively exposed photoresist layer toform a pattern. The photoresist composition includes a polymer resinhaving a first conjugated moiety, and a photoactive compound having asecond conjugated moiety. The first and second conjugated moieties arethe same or different and the first and second conjugated moieties areone or more selected from the group consisting of a polyacetylene, apolythiophene, a polyphenylenevinylene, a polyfluorene, a polypryrrole,a polyphenylene, and a polyaniline. In an embodiment, the actinicradiation is extreme ultraviolet radiation. In an embodiment, the methodincludes after selectively exposing the photoresist layer to actinicradiation to form a latent pattern and before developing the latentpattern heating the photoresist layer. In an embodiment, thepolythiophene, polyphenylenevinylene, polyfluorene, polypryrrole,polyphenylene, and polyaniline are substituted with one or moresubstituents selected from the group consisting of an alkyl group, anether group, an ester group, an alkene group, an aromatic group, ananthracene group, an alcohol group, an amine group, a carboxylic acidgroup, and an amide group. In an embodiment, the one or moresubstituents include an acid leaving group, and the photoactive compoundis a photoacid generator. In an embodiment, the photoresist compositionfurther comprises metal oxide nanoparticles and one or more organicligands.

Another embodiment, of the disclosure is a photoresist composition,including: a conjugated resist additive, a photoactive compound, and apolymer resin. The conjugated resist additive is a photobase generatoror photo-decomposable base attached to one or more selected from thegroup consisting of a polyacetylene, a polythiophene, apolyphenylenevinylene, a polyfluorene, a polypryrrole, a polyphenylene,and a polyaniline. In an embodiment, the polythiophene,polyphenylenevinylene, polyfluorene, polypryrrole, polyphenylene, andpolyaniline are substituted with one or more substituents selected fromthe group consisting of an alkyl group, an ether group, an ester group,an alkene group, an aromatic group, an anthracene group, an alcoholgroup, an amine group, a carboxylic acid group, and an amide group. Inan embodiment, the one or more substituents include an acid leavinggroup. In an embodiment, the conjugated resist additive has a weightaverage molecular weight of 50 to 1,000,000. In an embodiment, thephotoresist composition includes metal oxide nanoparticles and one ormore organic ligands. In an embodiment, the photoresist compositionincludes one or more solvents.

The foregoing outlines features of several embodiments or examples sothat those skilled in the art may better understand the aspects of thepresent disclosure. Those skilled in the art should appreciate that theymay readily use the present disclosure as a basis for designing ormodifying other processes and structures for carrying out the samepurposes and/or achieving the same advantages of the embodiments orexamples introduced herein. Those skilled in the art should also realizethat such equivalent constructions do not depart from the spirit andscope of the present disclosure, and that they may make various changes,substitutions, and alterations herein without departing from the spiritand scope of the present disclosure.

What is claimed is:
 1. A photoresist composition, comprising: aconjugated resist additive; a photoactive compound; and a polymer resin,wherein the conjugated resist additive is one or more selected from thegroup consisting of a polythiophene, a polyphenylenevinylene, apolyfluorene, a polypryrrole, a polyphenylene, and a polyaniline,wherein the polythiophene, polyphenylenevinylene, polyfluorene,polypryrrole, polyphenylene, and polyaniline are substituted with one ormore substituents selected from the group consisting of an alkyl group,an ether group, an ester group, an alkene group, an aromatic group, ananthracene group, an alcohol group, an amine group, a carboxylic acidgroup, and an amide group, and wherein the one or more substituentsinclude an acid leaving group.
 2. The photoresist composition of claim1, wherein the conjugated resist additive has a band gap of 0.3 eV to 4eV.
 3. The photoresist composition of claim 1, wherein the conjugatedresist additive includes a conjugated moiety attached to a photoacidgenerator, a photo-decomposable base, or a photobase generator.
 4. Thephotoresist composition of claim 1, wherein the conjugated resistadditive has a weight average molecular weight of 50 to 1,000,000. 5.The photoresist composition of claim 1, further comprising metal oxidenanoparticles and one or more organic ligands.
 6. The photoresistcomposition of claim 1, further comprising one or more solvents.
 7. Thephotoresist composition of claim 1, wherein: the polymer resin comprises

and the conjugated resist additive is selected from the group consistingof

where PAG is a photoacid generator, PBG is a photobase generator, andPDB is a photo-decomposable base, and R is the substituent.
 8. Aphotoresist composition, comprising: a polymer resin having a conjugatedmoiety; and a photoactive compound, wherein the photoactive compound isa photobase generator or a photodecomposable base; and wherein theconjugated moiety is one or more selected from the group consisting of apolyacetylene, a polythiophene, a polyphenylenevinylene, a polyfluorene,a polypryrrole, a polyphenylene, and a polyaniline.
 9. The photoresistcomposition of claim 8, wherein the polythiophene,polyphenylenevinylene, polyfluorene, polypryrrole, polyphenylene, andpolyaniline are substituted with one or more substituents selected fromthe group consisting of an alkyl group, an ether group, an ester group,an alkene group, an aromatic group, an anthracene group, an alcoholgroup, an amine group, a carboxylic acid group, and an amide group. 10.The photoresist composition of claim 9, wherein the one or moresubstituents include an acid leaving group.
 11. The photoresistcomposition of claim 9, wherein the polymer resin having a conjugatedmoiety is

and R is the substituent.
 12. The photoresist composition of claim 8,wherein the polymer resin having a conjugated moiety has a weightaverage molecular weight of 50 to 1,000,000.
 13. The photoresistcomposition of claim 8, further comprising metal oxide nanoparticles andone or more organic ligands.
 14. The photoresist composition of claim 8,further comprising one or more solvents.
 15. The photoresist compositionof claim 8, wherein the conjugated moiety is a repeating unit of apendant group on a main chain of the polymer resin.
 16. A photoresistcomposition, comprising: a polymer resin having a first conjugatedmoiety; and a photoactive compound, wherein the polymer resin having afirst conjugated moiety is


17. The photoresist composition of claim 16, wherein the polymer resinhaving a first conjugated moiety is substituted with one or moresubstituents selected from the group consisting of an alkyl group, anether group, an ester group, an alkene group, an aromatic group, ananthracene group, an alcohol group, an amine group, a carboxylic acidgroup, and an amide group.
 18. The photoresist composition of claim 16,wherein the photoactive compound is a photoacid generator.
 19. Thephotoresist composition of claim 16, wherein the photoactive compoundhas a second conjugated moiety.
 20. The photoresist composition of claim16, further comprising metal oxide nanoparticles and one or more organicligands.